My p5js clock draws over itself with every update.

Problem: As you can see on the link above, my clock updates just fine ... but the pixels created in previous loop are not deleted. It's very obvious if you look at the time in text near the bottom. If you wait till the analog clock goes from 60 seconds to the next minute's first second - the previous arc is not deleted and leaves behind a circle. Please see the attached screenshot for a visual representation.

Update: I have a feeling, it might have something to do with the lack of a background on my canvas. When I add background(0); to draw, it works just fine. But I don't want a black background, I want a transparent one. Using background('rgba(0, 0, 0, 0)') does not solve this either :(